Accession Number : AD0690877

Title :   INTERVAL ESTIMATES FOR THE P-N PLOTS OF FATIGUE DATA - WITH SPECIAL REFERENCE TO THE WEIBULL DISTRIBUTION,

Corporate Author : NEW YORK UNIV BRONX DEPT OF INDUSTRIAL ENGINEERING AND OPERATIONS RESEARCH

Personal Author(s) : Kao,John H. K.

Report Date : 15 JUL 1969

Pagination or Media Count : 37

Abstract : Probability papers for various fatigue life models such as normal, lognormal, exponential, gamma, Gumbel, Weibull distributions are graph papers with their coordinates modified so that, under the respective distributions, the probability failure, P in percent associated with the fatigue lifelength, N in number of cycles would form a straight line. Such graphical exhibits of fatigue data are known as P-N plots which are widely used by engineers to evaluate the fatigue characteristics of specimen, parts or structures. However, a P-N plot reveals only a series of point estimates for the true fatigue lifelength distribution function. In order to assess the 'goodness' of these point estimates, 'confidence intervals' are necessary. The report has concerned itself on three interval estimates. They are: (1) Nonparametric tolerance intervals, (2) Order statistic probability intervals, and (3) Parametric confidence intervals. These intervals are constructed around the P-N plots with a preassigned confidence coefficient. As the Weibull distribution is an important statistical model in fatigue testing, it is treated in some detail.

Descriptors :   (*FATIGUE(MECHANICS), STATISTICAL DISTRIBUTIONS), (*STATISTICAL DISTRIBUTIONS, *CONFIDENCE LIMITS), PROBABILITY DENSITY FUNCTIONS, RELIABILITY, FAILURE(MECHANICS), TOLERANCES(MECHANICS)

Subject Categories : Operations Research
      Mfg & Industrial Eng & Control of Product Sys
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE